this commit primarily uses frozen strings to reduce object creation during interpolation.
the :basename method now uses File.basename(file, ".*") rather than a Regexp. basename may be called multiple times.

by using the attachment name (symbol) and Class as keys we reduce the number of Strings created before hitting the cache

* Regression fix
* Add specs for intermediate_files var in Paperclip::Attachment

[fixes #1908]

  $ rspec spec/paperclip/integration_spec.rb --profile 1
  Testing against version 4.1.7
  ..................................

  Finished in 15.19 seconds (files took 0.60155 seconds to load)
  34 examples, 0 failures

  Top 1 slowest examples (9.54 seconds, 62.8% of total time):
    Paperclip Many models at once does not exceed the open file limit
      9.54 seconds ./spec/paperclip/integration_spec.rb:18

to

  $ rspec spec/paperclip/integration_spec.rb --profile 1
  Testing against version 4.1.7
  ..................................

  Finished in 10.95 seconds (files took 0.59585 seconds to load)
  34 examples, 0 failures

  Top 1 slowest examples (5.33 seconds, 48.7% of total time):
    Paperclip Many models at once does not exceed the open file limit
      5.33 seconds ./spec/paperclip/integration_spec.rb:18

Updates gemfiles to Ruby 2 hash syntax.

[closes #1700]

Both v1 and v2 of the AWS Ruby SDK accept the string literal AES256, no need to differentiate. (thank you, @trevorrowe)

According to the ImageMagick documentation the '@' flag is a special case that
can be used in conjunction with '>' to prevent IM from scaling an image up.
The '<' flag is ignored when using '@'.

http://www.imagemagick.org/Usage/resize/#pixel

This fixes the issue I reported in #1851

* update aruba methods for in_current_dir and check_file_presence
* switch rspec syntax from should to expect
* configure raise_in_transactional_callbacks if AR >= 4.2
* remove paperclip itself from Appraisal
This also updates Travis to use the default bundler (to enable caching) and to build primary rubies first

It should never be the case that `url` returns `nil`. If there is no url
that can be reasonable achieved, as is the case when the record the
attachment is attached to is unpersisted, then `url` should return the
default url.

For some reason the test in this PR would make all other ones blow up.
For reasons not fully understood at the time of writing, the alternate
spec I'd written doesn't. So, we'll replace that test with this one and
it'll be green.

Thanks to MORI Shingo of DeNA Co., Ltd. for reporting this.

There is an issue where if an HTML file is uploaded with a .html
extension, but the content type is listed as being `image/jpeg`, this
will bypass a validation checking for images. But it will also pass the
spoof check, because a file named .html and containing actual HTML
passes the spoof check.

This change makes it so that we also check the supplied content type. So
even if the file contains HTML and ends with .html, it doesn't match the
content type of `image/jpeg` and so it fails.

consistent with public URLs, this also changes the default behavior
for expiring URLs to use the https scheme rather than http.

Deprecation Warnings:

```
`failure_message_for_should` is deprecated. Use `failure_message` instead. Called from /Users/mugi/git/paperclip/spec/support/matchers/have_column.rb:11:in `block in <top (required)>'.
```

Prioritize MimeMagic over the `file` binary for content type detection
when it finds a match. Fall back to `file` if MimeMagic can't match
anything.

`file` incorrectly detects Open Office XML files (e.g., xlsx, docx) as
zip since they're implemented as zipped archives of xml files. MimeMagic
detects them properly.

* Uses Paperclip's Tempfile instead of Ruby's in Thumbnail
* Also includes a test for TempfileFactory to be sure it does not revert to similar behavior
* In the tests, give the OS some wiggle room in the Tempfile name to ensure the error does not occur before we are ready for it. The wiggle room is needed because the randomized part of the name has a variable number of characters.

Rescue only `NotIdentifiedByImageMagickError` in
`Attachment#post_process_style`. Other errors should bubble up, because
they are meaningless for the end-user, but important for the programmer.

Fixes #1352.